Conventional structural components cannot meet the strength demands of outer space without severe weight penalties, high cost, and/or slow fabrication. On the other hand, near zero CTE film based structural components, especially composite structures made from self-reinforcing multiaxially molecular oriented lyotropic liquid crystalline polymers and secondary reinforcing materials, demonstrate excellent intrinsic and tailorable properties which fulfill all of the strength and weight requirements envisioned for space based materials.
The multiaxially oriented film-based materials used in the construction of space based components are preferably prepared from rod-like extended-chain, aromatic--heterocyclic polymers, which are also referred to as lyotropic liquid crystalline polymers, and which are also referred to by the shorthand expression "ordered polymers." See for example, U.S. Pat. Nos. 4,533,692, 4,533,693, 4,533,724 to Wolfe et al., U.S. Pat. Nos. 4,051,108, 4,207,407, and 4,377,546 to Helminiak et al., U.S. Pat. Nos. 4,323,493 and 4,321,357 to Keske et al., U.S. Pat. No. 4,229,566 to Evers et al., U.S. Pat. No. 4,108,835 to Arnold et al., and U.S. Pat. No. 4,423,202 to Choe. The disclosures of these patents, to the extent necessary, are hereby incorporated herein by reference.
Molecularly oriented lyotropic liquid crystalline polymers have been under development for over ten years. Impressive successes have been realized in the synthesis of these rigid rod-like polymers, whose strong stiff molecules can be processed into extremely high strength, high modulus fibers.
One especially preferred molecularly oriented liquid crystalline polymer of this type is poly paraphenylenebisbenzothiazole or PBzT. The processing of PBzT into fibers has been of special interest to many investigators, and is currently under development for large quantity production.
On the other hand, the processing of ordered polymers such as PBzT into non-fiber components is still in its infancy. Most current investigative work is directed at attaining only film type materials.